Ford family patriarch William Clay Ford died Sunday at his home in Grosse Pointe Woods, a Detroit suburb. The cause of death was pneumonia. He was 88, and five days from his 89th birthday. Mr. Ford’s passing marks the end of an era at Ford Motor Company. He and brothers Henry II and Benson were the sons of Edsel Ford and grandsons of company founder Henry Senior.

Mr. Ford was also the father of William Clay Ford Jr., the company’s executive chairman.

Although upstaged by Henry II and perhaps more widely remembered as the owner of the Detroit Lions football team, William Clay Ford made numerous contributions to the fortunes of the family’s automotive enterprises over the years.

Family legend has William Clay Ford getting his first driving lesson from his grandfather Henry, and his first airplane experience in a Ford Tri-Motor with Charles Lindbergh at the controls.

Following a brief stint in Navy at the end of World War II, Ford attended Yale University, and, already a board member, joined the family business upon graduation in 1949.

William Clay Ford joined his brothers Benson (left) and Henry II (right) at the family business in 1949.

His first job was with the company’s advertising and sales organization. Ford became a corporate vice president in 1953. Like his father, he had an eye for design and eventually headed Ford’s design committee, a position he held for 32 years.

Mr. Ford’s most tangible achievement during that period was the Continental Mark II. A belated follow-up to the original Mark I Continental, the second generation was a response to the 1953 introduction of the first Cadillac Eldorado.

Appointed as head of a Special Projects Office in 1952, William Clay Ford eventually set up what amounted to a separate manufacturing operation—the Lincoln Continental Division—to create and build the Mark II. He refrained from drawing stylists employed at other Ford divisions, instead enlisting outsiders, including Gordon Buehrig of Auburn-Cord-Duesenberg fame.

The Mark II was a knockout, but with a price tag of almost $10,000—nearly $3500 more than the Eldo—the big coupe lasted just two years. Total production ended in 1957 at 3014 cars, and the Continental Division was out of business.

Though the Mark II was Mr. Ford’s only direct role in vehicle design and production, he influenced many of the company’s uninhibited concept cars—the Lincoln Futura (1955), Ford Nucleon (1957), and the Ford Seattle-ite XXI (1962), among others.

William Clay Ford (right) took over Ford’s product planning and design operations in 1957.

And he went on to hold other positions in the company’s hierarchy. He was named chairman of the board’s executive committee in 1978, vice chairman in 1980, and chairman of the finance committee in 1987.

He also served as chairman of the board at the Henry Ford Museum from 1951 to 1983, the longest tenure in the museum’s history, and was its biggest donor. He retired as vice chairman six years later and stepped down from the finance committee chairmanship in 1995, but remained on the board until 2005.

Though financially successful, Ford’s stewardship of the Detroit Lions was undistinguished in terms of wins and losses. He acquired the Lions in 1964 for a reported $4 million. Since then, under a variety of executive management and coaches, the team has failed to win an NFL or Super Bowl championship, scoring its last playoff victory in 1992, 38-6 against Dallas.